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Module 8: LNG Vehicle Systems and Safety Practices

Lesson 8.3: Unsaturated LNG Fuel Systems and Components

What is ▪ LNG that has NOT been slightly warmed at the LNG station by heat exchanger(s)
Unsaturated LNG? ▪ Unsaturated fuel is colder than saturated
o Saturated refers to the amount of heat that has been absorbed by the fuel

Comparing Saturated Unsaturated
Saturated and (Warmed ~ -200⁰F) (Cold ~ -230⁰F)
Unsaturated LNG ▪ No accumulator ▪ Accumulator required
▪ LNG storage tank ▪ LNG storage tank with pump
▪ Fuel delivered via tank pressure ▪ Fuel delivered via pump
▪ Tank pressure created by mechanism
warming the fuel ▪ Pump mechanism operated by
▪ Low pressure into airstream engine’s power steering pump
▪ Requires an ignition system ▪ High pressure direct injection
▪ Dedicated CNG operation only – into engine cylinder
no diesel on board ▪ Requires diesel as ignition source

Unsaturated LNG
Fuel System
Overview

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